P1265: UNRELATED FEMALE-TO-MALE BONE MARROW TRANSPLANTATION SHOULD BE PREFERRED OVER CORD BLOOD TRANSPLANTATION IN MALE RECIPIENTS.
Authors: Masaharu Tamaki, Yu Akahoshi, Yosuke Okada, Naoyuki Uchida, Masatsugu Tanaka, Noriko Doki, Masashi Sawa, Yumiko Maruyama, Yasunori Ueda, Shigesaburo Miyakoshi, Yuta Katayama, Toshiro Kawakita, Takafumi Kimura, Makoto Onizuka, Takahiro Fukuda, Yoshiko Atsuta, Ryu Yanagisawa, Kimikazu Yakushijin, Junya Kanda, Hideki Nakasone
Journal: HemaSphere (2023)

Topic: 22. Stem cell transplantation - Clinical Background: Allogeneic hematopoietic stem cell transplantation from female donors to male recipients (female-to-male allo-HCT) is a well-established risk factor for a higher incidence of non-relapse mortality (NRM) and chronic graft-versus-host disease (GVHD). On the other hand, unrelated cord blood transplantation (UCBT) was associated with a lower incidence of chronic GVHD. It remains to be elucidated that UCBT can overcome an inferior survival outcome of unrelated female-to-male bone marrow transplantation (UFMBMT). Aims: We compared survival outcomes between UCBT and UFMBMT, and elucidated which donor sources should be selected when only sex-mismatched donors are available. Methods: Clinical data were provided by the Transplantation Registry Unified Management Program (TRUMP) of the Japanese Society for Transplantation and Cellular Therapy (JSTCT) and the Japanese Data Center for Hematopoietic Cell Transplantation (JDCHCT). We retrospectively evaluated male allo-HCT recipients who underwent UCBT or UFMBMT between 2012 and 2020 in Japan. Survival outcomes were compared among the UCBT, HLA-matched and -mismatched UFMBMT groups. Subgroup analyses according to the myeloid disease (acute myeloid leukemia, myelodysplastic syndrome, chronic myeloid leukemia and myeloproliferative neoplasm) and lymphoid disease (acute lymphoblastic leukemia and malignant lymphoma) cohorts were performed in the same manner. Results: There were 2517 cases in the UCBT group, 456 cases in the HLA-matched UFMBMT group and 457 cases in the HLA-mismatched UFMBMT group. HLA-mismatched UFMBMT was significantly associated with a decreased risk of relapse (HR 0.74 [95% CI: 0.57 – 0.98], P= 0.033) and HLA-matched UFMBMT had the tendency of a decreased risk of relapse (HR 0.78 [95% CI: 0.61 – 1.01], P= 0.059). HLA-matched UFMBMT was also associated with favorable OS (HR 0.82 [95%CI: 0.69 - 0.97], P= 0.021). Similar to the whole cohort, HLA-matched (HR 0.54 [95% CI: 0.31 – 0.95], P= 0.032) and -mismatched UFMBMT (HR 0.41 [95% CI: 0.22 – 0.76], P= 0.0046) were significantly associated with a decreased risk of relapse in the lymphoid cohort. HLA-mismatched UFMBMT was also significantly associated with superior OS (HR 0.67 [95% CI: 0.46 – 0.99], P= 0.043). On the other hand, the significance of relationship between the donor sources and survival outcomes was not confirmed in the myeloid cohort. Summary/Conclusion: UCBT was significantly associated with an increased risk of relapse compared with UFMBMT, especially in the lymphoid cohort. The difference of GVL effect by H-Y immunity according to donor sources might contribute to the difference in clinical impact. It might be desirable for patients who could sufficiently wait for donor coordination to select BMT rather than UCBT, even if only unrelated female donors are available for male recipients Keywords: Allogeneic bone marrow transplant, Gender, Cord blood transplant